This research involves the study of the structure, localization, supramolecular organization and physiological function of skeletal and contractile cytoplasmic fibers in cells grown in vitro. The long term goal of these studies is to determine to what extent these proteins are involved in controlling the motility and behavior of normal and virus-transformed cells. Attempts are being made to correlate function with structure through the use of microscopical, physiological, biochemical and immunological techniques. BIBLIOGRAPHIC REFERENCES: Goldman, R.D. 1975. The use of heavy meromyosin binding as an ultrastructural cytochemical method for localizing and determining the possible functions of actin-like microfilaments in non-muscle cells. J. Histochem. and Cytochem., 23:529-542. Albrecht-Beuhler, G. and Goldman, R.D. 1976. Microspike-mediated particle transport towards the cell body during early spreading of 3T3 cells. Exptl. Cell Res., 97:329-339.